Polymerase Chain Reaction (PCR) Assays for Hepatitis C Virus (Qualitative)
The presence of anti-HCV antibodies in patients infected with HCV has led to the development of the immunoserological tests that are specific for these antibodies. Implementation of these tests already has reduced the incidence of post-transfusion hepatitis worldwide. Additional supplement testing is performed using the RIBA (Recombinant Immunoblot Assay) to further evaluate samples that are repeatedly reactive in the antibody-screening assay. Recent evaluations have shown that interpretation of these immunological tests is difficult, since 25-90% (depending on the risk group under evaluation) of samples that are repeatedly reactive in the screening assay are negative upon supplemental evaluation with the RIBA assay (McHutchison et al., 1992 and Chaudray et al., 1993).

Immunological testing is a measure of prior exposure to HCV infection, but cannot be considered a marker for current infection. At the present time, an immunological assay for direct detection of HCV antigen is unavailable. Furthermore, in case of acute HCV infection, individuals may fail to produce antibody to HCV( Mitsui et al., 1992), making diagnosis of current HCV infection impossible using immunoserological techniques. Alternatively, detection of HCV by Polymerase Chain Reaction (PCR) may be a marker of current infection. Using PCR, it has been possible to detect HCV viremia prior to immunological sero-conversion( Puoti et al., 1992 and Young et al., 1993), and to detect fluctuation of viremia in antibody-positive chronic HCV patients undergoing therapy with interferon( Shindo et al., 1991).

Since PCR is able to amplify HCV RNA directly, independent of the patient's immunological status, a PCR-based test is valuable in detection of HCV of RNA in immuno-compromised patients.

COBAS AMPLICOR™ HCV Test, v2.0

	The first automated qualitative nucleic acid-based Hepatitis C test to be approved for marketing in the U.S. by the FDA
	Detection of HCV RNA levels as low as 50 IU/mL
	Automated HCV RNA detection which may contribute to greater laboratory productivity
	Sensitivity, reliability and standardization in every test
	The ability to accurately diagnose current infection and follow response to treatment
	Quantification of viral load levels for treatment, prognosis and monitoring

	Chaudray, R. K., Andonov, A. and MacLean, C. 1993. Detection of hepatitis C virus infection with recombinant immunoblot assay, Synthetic immunoblot assay, and polymerase chain reaction
	McHutchison, J., Person, J., Gocindarajan, S. et al. 1992. Improved detection of hepatitis C virus antibodies in high-risk populations. Hepatology 15: 19-25
	Mitsui, T., Iwano, K., Masudo, K. et al. 1992. Hepatitis C virus infection in medical personal after needlestick accident. Hepatology 16: 1109-1114
	Puoti, M., Zonaro, A., Ravagil. et al. 1992. Hepatitis C virus RNA and antibody response in the clinical course of acute hepatitis C virus infection. Hepaotology 16: 877-881
	Shindo, M., DiBisceglie, A.M., Cheung, L. et al. 1991. Decrease in serum hepatitis C viral RNA during alpha-interferon therapy for chronic hepatitis. Annals of Internal Medicine 115: 700-704
	Young, K.K.Y., Resnick, R. and Myers, T.W. 1993. Detection of hepatitis C virus RNA by a combined reverse transcriptase-polymerase chain reaction assay. Journal of Clinical Microbiology 31: 882-886